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6 Sheets-Sheet 1. A. PRATT 8v JQJGHNSTON.

ROLL GROOVING MAGHIIN.

(No Model.)

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(No Model.) Y 6 Sheets-Sheet 2. I'. AL PRATT 8v J. JOHNSTON.

ROLL GROOVING MACHINE.

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d d 0 M m ROLL GROVIVNG MACHINE.

` No. 504,172. Patented' Aug. 29, 1893.

www? @Hf m14@ .M. Mm My@ (No Model.) 6 Sheets-Sheet 4.

` F. A. PRATT & J. JOHNSTON.

ROLL GfRO0VIN(:rl MAGHINB. I

` No. 504,172. Patente-d Aug, 29, 1893.

(No Model.) e'sneets-sneet 5.

I'. A. PRATT 8v J. JOHNSTON.

ROLL GROOVING MACHINE.

Patented Aug. 29, v 1893.

I `6 Sheets-Sheet 6. F. A. PRATT & J. JOHNSTON.

'ROLL GROWING MACHINE.

No. 504,172. Patented Aug. 29, '1893.

(No Model.)

Inventors: WZ A Runas Pra/t. L -ZOJJ'J Ja/v Ja/zrzson.

. their .ttorzzcyl UNITED STATES PATENT OFFICE.

FRANCIS A. lPRATTAND JOHN JOHNSTON, OF HARTFORD, CONNECTICUT, A'SSIGNORSTO THE PRATT` da WHITNEY COMPANY, OF SAME PLACE.

RoLL-G'RoovlNe MACHINE.

' SPECIFICATION formingv part of Letters Patent No. 504,172, datedAugust 29,1893.

Application fled May 17. 1893. Serial No.. 474,557. (No model.)

. certain new and useful Improvements in Roll- Iol Grooving Machines, ofwhich the following is a specification. l

This invention relates to machines for spi- "rally groovingjrollersforgrinding-mills; and

, itis', inv part, in the natureofan improvement fon the machinefforasimilar purpose described in Letters Patent of vthe United States No.256,165, granted April 11, 1882, to John R. Reynolds, assignor to ThePrattn Whitney Company, of Hartford, Connecticut.

In the drawings accompanying and form,- ing a part of thisspecification, Figure 1 is a plan View of a roll-groovingmachineembodying our present improvements. Fig. 2 is a side elevation ofthe machine, as seen from below in Fig. 1; this view is from therighthand side of the machine, and shows the table run back ready forbeginninga cut upon the roll carried thereon. Fig. 3 is an elevationsimilar to Fig. 2, showing the table run forward as at the end of theout; in this View the right-hand column is removed, for the purpose ofmore fully illustrating the arrangement and operation of the details.Fig. 4 is a front end-elevation of the machine, as seen fromtheleft-hand in Figs. l, 2 and 3. Fig. 5 is a rear end-elevation of themachine, as seen from the right-hand in Figs. 1, 2 and 3. Fig. 6 is anenlarged View of a portion of Fig. 5, showing some details in section,for illustrating the construction and operation of the same. Fig. 7 is asectional plan View of the middle portion of the frame of the Inachine,together with the principal portions of the table driving and reversingmechanism. Fig. 8 is an enlarged inverted plan View of thetraversing-bar. Fig. 9 is a section of the traversing-bar, in line a a,Fig. 8. Figs. l0

Y and 11 are detai-l views of parts of the spacing mechanism. Fig. 12 isa sectional end View of the worm,its carrier guides and support.

Similar characters designate like parts in all the figures.

The roll-grooving machine, as will be hereinafter more fully described,embodies some of the features or elements found in a double tool-postside-planer of ordinary construction; as herein shown it comprises theusual frame or bed B, having the uprights G, H, for supporting thetool-carriers I, J, a driving-mechanism for imparting a reciprocatingmovement to the table or bed 3, which drivingmechanism consists,essentially, of xed and loose-pulleys with the requisite speed-reducinggears in communication with a rack fixed to the under side of thereciprocating table and Vhaving suitable bearings in the frame of themachine, and suitable reversing-mechanism, which may be substantiallysuch as hereinafter more fully described. Y

The roll A, the surface of which is to be cut or grooved,has anend-bearing shaft which is supported at its ends between the centers ofthe tail-stock K and the revolving head 6. This head has adouble-splined shaft 7, supported in bearings 8, all of which are ofusual construction and secured to the table in the usual manner;supplemental bearingsformed in the upper end of uprights 4, 5,adjustably secured to the table, are provided to support lthe shaft atpoints near the end ofthe roll.

Fixed to the rear end of the table 3, is a block D having a horizontalbearing 8 therein which forms a support for the hub of a worm-wheel 57,through which the end of the splined shaft7extends. This block forms asupport for the mechanism that imparts a rotary movement to the roll A,as will be hereinafter more fully described.

Driving mechanism-The drivin g mechanism for imparting a reciprocatingmotion to the table 3, consists, in the preferred form thereof hereinshown, of the main-shaft 12 which extends horizontally and transverselythrough, and is journaled in suitable bearings attached to the frame ofthe machine; said shaft extending beyond the sides of the frame, andhaving the fast and loose-belt pulleys 13 and 13 at one end, and thefast and loose pulleys 14 and 14 at the opposite end, which pulleys aresecured in place on the shaft in the usual way. A pinion 17 is shownkeyed to the shaft 12, near the end, provided with'pulleys 14 14; aspurwheel 26 is se- IOO cured to a shaft 28, mounted in bearings 29 and30 upon the frame, as clearly shown in Fig. 7, in position to mesh withthe teeth of the rack 31; and a train of speed-reducinggearing isprovided intermediate to, and in mesh with, the pinion 17 upon themain-shaft, and the spur-wheel 26, which train of gearingcomprises agear-wheel 16 in mesh with the pinion 17 and mounted upon a shaft 18journaled in suitable bearings upon the frame, and having a pinion 2O atthe inner end of said shaft in mesh with a gear wheel 21 mounted uponthe shaft 25, supported inbearings 22, 23 and 24 in the frame, which`shaft has a pinion 21 thereon that meshes with spur-wheel 26. Thismechanism is, and may be, of any usual construction and arrangement.Secured tothe outer end of the shaft 25, (as shown in Figs. 3 and 7,) atthe outside of the frame is a wheel 27', upon which are two radiatingteeth` arranged at a suitable distance relative to each other, thefunction of which isto effect an outward impulse of the tool-carriers tothrow them out of contact with the work at the end of the stroke and atthe moment the shifting of the belt takes place to obviate the draggingof the tool on the return stroke. Said wheel will, in practice, beconnected by means of a cord and pulleys, with the tool-carriers. Theconstruction and operation of the device for ac complishing this endwill be similar to that of other well known and like devices in ordinarycircular boring mills and planers, and as it forms no essential part ofmy present invention, a detailed description thereof is deemedunnecessary.

Shifting mechawism-Formed longit udinally in the side of the bedor-table 3, is aslot 32, and adjustably-secured in said slot are ltwodogs 10, and 11 which are arranged at the proper distance for the lengthof travel it is desired to s ecure to the roll being operated upon.Movably secured upon guides upon the framework, is a sliding block Lwhich has, at one end, a stud 42 upon which is pivoted one end of anoperating lever pivotallysecured at its opposite end, as at 42', to abearing upon a plate 43 supported in bearings 43 and 43, secured to theframe, which plate is capable of horizontal reciprocation in saidslides. Formed in said sliding plate 43 is a cam-groove or slot 44,preferably of Zshape,

` which may,

and movably seated in said groove 44, at the proper relative positionscorresponding to the axial lines of the shipper rods 45 and 46, areguide-blocks 48 and. 49. These guide-blocks,

anti-friction bearings in the slot 44, are secured to the shipper-rods45, 46, which have bearings transversely in the frame and carry at theirends the belt-Shifters or Iingers 47 and 47', respectively. By thisconstruction and arrangement of shifting-mechanism, it will be seen thatmotion imparted to the sliding block L through contact therewith of thedogs 10 and l1, in either the forward,`or re- `at 35 upon the frame ofthe machine.

l block L.

if desired, have rollers to form Y turn movement of thebed or table 3,`will be be transmitted, through the medium of the lever 41, to thesliding-plate 43 moving it either backward or forward in the samedirection that the table is moving; and the sliding-plate 43, throughthe medium of the slot j 44 and the sliding block secured to the shipperrods moving in said slot, will move the shipperrods transversely, inwardor outward,

together with the Shifters 47 and 47 which will shift the belt from oneset of pulleys to the pulleys driven in the reverse direction, thusimmediately imparting a reverse movement to the train of gearing in meshwith the main-shaft 12 and rack 31 upon the table which will move saidtable in an oppositedi rection. Mounted in. thesl'iding block L upon theframe isa spring-controlled rod or plunger 3S, which extendsthroughbearingstherein, and has a nut 39 at one end and a head 37 at itsopposite end to limit its reciprocating movement. A spiral spring 40`around said rod and bearing against the head 37 and inner wall ofV theblock L tends to retain the bolt in an outward position, or in theposition shown in Fig. 7, the function of which will be hereinafter morefully explained. Formed upon, or secured to the under sideof the slidingblock L, is a projecting catch 33', which, in the forward position ofthe bed, and during the operation of cutting the roll, is engaged byacatch 32 upon the rearwardly projecting arm of a bell-crank lever 34fulcrumed The catch upon the lever-arm is normally held in engagementwith the catch upon the sliding block L by a spring secured at one endto the frame and at its other end to a projection upon the lever, asshown in Fig. 2; By reterence to said Fig. 2, it will be seen that thespring-controlled rod 38 is projected forward with its head 39 abuttingagainst the, rear end of the sliding block, and that the upwardlyprojecting arm of the bell-crank is thrown forward and the catch uponthe arm34 thereof is in engagementwith the catch upon said When thetable 3 is near the rear end of its stroke, as shown in Fig. 3, aprojection upon the dog 10, secured to the table as before described,will, after the spring-control-led rod 3S has been pressed backwardalmost the entire extent of its rearward movement by the dog l0, abutagainst the upwardly projecting arm of lever 34 and throw thecatch uponarm 34 out of engagement with catch 33 upon the sliding-block L, whichblock being thus released is immediately driven backward by reason ofthe stress of the spring, thereby giving a quick impulse to the lever41in connection with the plate 43, and through the medium oftheshipper-rods, quickly shifting the belts and obtaining animmediatereverse movement of the table 3. The dog 11 will, on the returnmovement of the table, at the proper time, or when near the extreme endof its stroke, come in contact with the rear end of the sliding block Lwhich carries IOO IIO

the backward movement of the table, or while1 the roll is being operatedupon.

Mechanism forl rotating the roll. As a means for imparting the requisiterotary movement to the roll A, the sliding table has adjustably securedto it near its rear end, a block D, of any suitable construction, havinga horizontal bearing 8 formed therein, in which is supported the h-ub ofa worm-wheel 57, through which extends the splined-shaft 7 which isconnected at its forward end to the revolving head 6 that supports oneend of the arbors of the roll A as before described. Secured tothe rearface of the block B by means of screws 67 and 68 or equivalents, are twoguide-plates 67 and 68, see Fig. 6, which receive between them atraverser or sliding-head 69, having at its ends op,- positelyprojecting bearings 70 and 70 which supports the journals of a worm orscrew 7l. This worm is held against longitudinal movement awithin itsbearings by a shoulder 72 at one end, and a collar, or nut and Washer 73at its opposite end. The threads of the worm are in mesh with the teethof, and impart a rotary movement to the Worm -wheel 57, and, through themedium of the splined-shaft 7, rotates the roll A, as will behereinafter more fully described. This worm has an extension or shaft 74with longitudinalsplines thereon, extending through grooves in a collarjournaled, and free to rotate, in a bearing 77, se-

cured to the block D,` said construction and arrangement of the wormpermitting a rotary and longitudinal movement to be imparted thereto, aswill be hereinafter more fully eX- plained. The traverser orsliding-head 69 will preferably have a laterally-.projecting hood 100which overhangs the worm 71, and formed upon said hood, centrallybetween its ends, and vertically central with relation to the axis 'ofthe Worm, is an upwardly projecting boss 101, which receives thescrew-threaded lower end of a stud or block 102, that has a slidingbearing at its upper end in a longitudinal groove 103 formed in thelower face of a traversing-bar E. This traversing-bar ispivotally-supported at its center in a bearing near the end of theoverhanging, rearwardly-projecting arm F which is bolted to,

Y and supported upon pillars G, H, or uprights near the center of theframe B, as shown in the drawings. Formed in the end of the overhangingarm F is a radial slot 105 which forms a bearing for the stud 109 whichextends through the traversing-barin the rear of its central support,which stud 109 is secured in the bearing-slot 105 by a nut. .Thisconnection between the traversing-bar and overreaching arm F at one sideof the pivotal connection, vforms .a supplemental support for, andpermits the said traversing-bar to be adjusted and secured inY theadjusted position at .any inclination with relation to a horizontal linedrawn longitudinally through the center of the table 3, and axis of theroll A to be operated upon, such adjustment regulating, as will behereinafter more fully explained, the transverse reciprocation of theworm 71, and consequently the rotation of the worm-wheel 57 and roll Awhich determines the extent of inclination or pitch of the groovesformed in the roll bythe cutters. The sides of the over-reaching arm F,and the traversing-bar E near the point of their pivotal connection willpreferably be curved as shown in Fig. 1, the radious being concentrictothe axial center of the connection. Formed upon said curved portionsare graduating marks to register, one with the other, by means of whichthe operation of adjusting the bar to the desired inclination to producethe requisite rotary movement of -the roll and a given pitch to thegrooves to be formed therein, is greatly facilitated. It will beobserved, by reference to the drawings, that as the table that supportsthe roll is moved backward, the block 102 (being, we will assume, in theposition in the traversing-bar E shown in Fig. 2,) will travel, inconsequence of the inclina` tion of said bar, longitudinally, but'at anangle to the line of movement of the bed, which will impart atransversemovement to the traverser or sliding head 69 in the guides upon thesupporting-block D, together with worm 71, which being in mesh with theworm-wheel 57 rotates said wheel, together with its splined shaft 7, andthrough itimparts a rotary movement to the roll A. The worm in thisoperation acts as a rack to impart movement to the worm-wheel. To changethe pitch of'the groove to be cut in the roll, it is simply necessary toloosenthe nut upon the stud 109 in the radial bearing 105 at the extremerear end of the over-hanging arm F, and turn said bar upon its axis tothe proper degree of inclination (which can be determined bytheindication marks) to insure a greater or less transverse reciprocationto the traverseras the block 102 which being seated -inthe groove 103 inthe bar E, and connected with the said traverser, limits the backwardand forward movement of the Worrnconnected with the traverser as beforedescribed, and consequently limits the extent of the revolution of theworm-wheel shaft and roll A in a degree proportionate to the movement ofthe traverser.

Spdcing-mechamsma'lhe spacing mechanism for imparting an' intermittentrotary movement to the roll A, comprises,'essentially, a ratchet-Wheel76 keyed to the collar or revoluble bearing 75 splined to lthe end ofthe worm-shaft 74,-as shown in Fig. 6; a pawl 83 in engagement with saidratchet-wheel, and pivoted to the endof an arm 83,.secured to the hub ofa pinion .81, loosely mounted upon said bearing 75, and a sector ortoothed seg- IOO IOS

ment 8O pivotally mounted upon a shaft or stud S4 iixedly secured toasupport upon the block D or table of the machine. Secured to the hub 86`of the sector, is a sector-lever 86 having at its free end a stud uponwhich is mounted a friction-roller S7, which, as the table 3 is movedforward rises upon the incline or cam-face 65 of a plate 65 bolted tothe frame. The said cam-face moves the lever 86 upward and the sector onits axis toward the front of the machine, and, through the medium of thepinion 81, carries the pawl 83 around and imparts a rotary movement tothe ratchet with which it is engaged, thereby revolving the shaft 74 therequisite distance for spacing. iVhen the lever S6, through the backwardmovement of the table, is released from the incline it returns to itsnormal position which automatically rotates the pinion 81 and allows thepawl to take up another position upon the ratchet ready to turn it whenthe lever again acts by riding up the incline. The `outer end of the hub86 is of sufficient internal area to permit the insertion of the spiralspring S8, which has a bearing at one end in the shaft 84, and at itsopposite end, in a cap S9, herein shown as secured to the hub bya screw90. The tension of this spring normally retains the sector 80 in theposition shown in Fig. 3, until the roller 87 upon the sector-levercomes in contact with the inclined face ofthe plate 65', when thetension of the spring is overcome by the leverage, and the sectorallowed to partially rotate on its axis. Fixed to the shaft 84 isastop-arm 113 and upon the lever 86 is a stop-screw 112, which, in themovement of said lever contacts with the said stoparm and regulates thethrow thereof. By this arrangement of stop and stop-arm, the throw ofthe lever 86 and its sector 80, may be quickly adjusted, whichadjustment will gage the distance between grooves upon the roll, as itlimits the intermittent rotary movement of said roll. Both the stop-arm118, and sector-lever 87, will preferably be secured, one to the shaft,and the other to the hub of the sector in such manner that they may beadjusted as may be desired relatively to each other. Thespacing-mechanism is so constructed, arranged,

and timed, in its movements, with relation to the other actuating partsof the machine, that it acts intermittently to rotate the roll thedesired distance, said movement taking place only at the time the rollstops in its forward movement and just prior to the beginning of thecutting of the groove, at which time the devices hereinbefore described,for giving a continuous rotation to the roll, as the table'travelsbackward and forward, are at r'est.

The operation of the machine is as follows:-

The roll or piece to be operated upon is placed with its shaft or arborin the bearings 4, 5, and accurately centered by the center-points uponthe tail-stock and revolving head, the forward end of the shaft beingmade fast to the revolving head by a dog or fasteningpiece in the usualmanner. The carriage is then brought to its extreme forward position,iasshown in Fig. 2, and the traversing-bar Eis set to the proper degree ofinclination with relation to the overhanging arm F and center ofmovement of the table to secu re the proper rotation of the roll Thetool .is then set to take a slight scraping cut upon the roll, whichroll is run backward to the complete end of its stroke. The roll is thenbrought back to its first position and turned a one-half revolution orone hundred and eighty degrees, (which may be accurately determined bysuitable pointers or marks upon the worm-gear mechanism) whichrevolution will bring it in exact position to match the center lineofthe cutting-tool. This slight cut is then used as a gage whereby theothercuttiug-tool may be set which permits the tools to produce two cutsor corrugations diametrically opposite, which grooves, when the roll isreversed, will be symmetrically correct with respect to each cuttingtool; that is,-the corrugations will come out as perfect as they wouldif only one tool were used, thus facilitating the work. By supportingthe traversing-bar E to and under an overhanging arm secured to theframeof the machine and above the work-carrying parts, and supporting thesliding head which carries the worm that imparts a rotary movement tothe shaft and roll to be operated upon, the lateral strain is equalizedand the vibration of the shaft and roll, due to the lateral pressure ofthe cutters upon theiroll1 is materially reduced, if not'entirelyobviated; this is a great desideratum, as it insures an evenness anduniformity of cutting practically impossible with machines having nosupport for the upper parts of the carriage or devices which control therotary movement of the roll being operated upon.

Having thus described our invention, we claim- 1. In a roll groovingmachine, the combination with the main framework and with thework-carrying table sliding thereon, of an overhanging-arm, atraversing-bar pivotally supported and adj nstably-secured to and undersaid arm, the work-actuating shaft carried on the table, the worm-wheelon said shaft, the sliding worm engaging said wormwheel, means forsliding the worm by en- IOO IIO

gagement with the traversing bar, and means tion with the frame B, thesliding table 3 thereon and work-operating shaft 7, of anoverhanging-arm secured to the frame having a bearing for pivotallysupporting a traversing-bar and having the radially slotted bearing 105,the grooved traversing-bar E pivotedto said overhanging-arm and havingadjustable connection with the bearing 105, and mechanism, substantiallyas described, interposed between the bar E and table 3 and having asliding connection with the bar E and shaft 7, all constructed andarranged substantially as described to impart a rotary movement tosaidshaft, substantially as and for the purpose specified.

4. In a roll grooving machine, the combination with the frame B, slidingtable 3 and over-reaching arm F supported upon pillars or uprightssecured to the frame B, of the slotted traversing-bar E pivotally andadj ustably secured to the underside of the arm F; the block D havingthe bearing 8 therein; the worm-Wheel 57, the hub of which issupportedin the bearing 8; the splined shaft 7 supported in said hub;the worm 7l supported in bearings upon the traverser or sliding block 69supported in slides upon a block D; a stud or block 102 secured to thesaid traverser as shown and having a sliding bearing in the'groove inthe traversing-bar, arranged as described to impart a rotary motion tothe shaft 7, and mechanism connected With the shaft 74 and table toimpart an intermittent rotary movement to the shaft 7 and connectedroll, allsubstantially as, and for the purpose described.

5. In a rollgrooving machine, the combination with the frame B andsliding table thereon, of the overhanging arm F; the slottedtraversing-bar pivotally and adj ustably secured thereto; the block Dsecured to the bed, the splined shaft 7 having a worm-wheel thereonsupported in a bearing in the block D; the worm 71 supported in bearingsin the traverser 69 sliding in guides transversely secured to the blockD; the sliding connection 102 between the traversing-bar and traverser,and a pawl and ratchet mechanism secured to the end of the worm-shaft74, and the devices to impart an intermittent rotary motion to theratchet and worm-shaft, substantially as, and for the purpose described.

6. In a roll grooving machine, the combination with the frame B, slidingtable 3 and the transverse worm-shaft, arranged as described, of amechanism to impart an intermittent rotary` movement to said shaft,comprising a spring-actuated toothed sector pivotally-secured to a studor shaft fixed to the table; a pinion loosely mounted upon a sleevesecured to the worm-shaft in mesh with said sector; a pawl supportedupon an arm fixed to the lsaid pinion; a ratchet-Wheel fixed to thesleeve secured to the said Worm-shaft and engaged by said pawl; a leversecured to, or forming a part of, the sector, and a plate secured to theframe having an inclined face to ift the sector-lever and impart arotary motion to the worm-shaft, substantially as described.

7. The combination with the pinion 81 and with a ratchet mechanismsecured to the Worm shaft, of the toothed sector loosely mounted upon ashaft secured to the table and having a spiral-spring secured at one endto the sector and at its other end to the shaft 84, and adapted toimpart a return movement to the sector after it has been turned torotate the shaft 74, substantially as and for the purpose described. i

8. In a roll-grooving machine, the comblnation with the main frame-work,and With the work-carrying table sliding thereon, of the overhangingarm,the traversing-bar supported under said overhanging arm andadjustablethereon, the work-actuatlng shaft carried on the table, the worm-Wheelon said shaft, the sliding worm engaging said Worm- Wheel, means forsliding the Worm by engagement with said traversing-bar, and means forintermittently revolving the Worm, substantially as described.

A9. In a roll-grooving-machine, the combination with the main frame andthe Workcarrying-tablev sliding thereon,and withthework-actuating-shaft, of the overhangingarm, thegrooved traversing-barpivotally and adjustably secured to said overhanging-arm, and mechanismintermediate to said traversing-bar and work-actuating-shaft, adaptedfor rotating said shaft at varying speeds, and mechanism forreciprocating the table, substantially as and for the purpose described.

10. In a roll-grooving-machine, the combination with the main frameworkand the Work-carryingtable sliding thereon, and with thework-actuating-shaft, of the overhanging arm, the traversing-barpivotally supported under said arm and adj ustably secured thereto,intermediate mechanism movably connected with said traversing-bar andWork-holdingshaft adapted for imparting a continuous rotary movement tosaid shaft during the longitudinal reciprocation of the table, forthepurpose of forming grooves of uniform pltch in parallel lines, andindependent operable` mechanism in connection with theshaft-turning-mechanism aforesaid, and with the sliding table forintermittently rotating the workholding-shaft for spacing the groovesformed in the work, substantially as described.

11. In a roll-grooving-machine, the combination with the main frameworkand the Work-carrying-table sliding thereon, of anactuating-shaftjournaled in suitable bearings and having a driving-wheelthereon, a traversing-bar pivotally and adjustably supported above saidshaft, a rack intermediate to said traversing-bar and driving-wheel, andin position for rotating said shaft during the reciprocations of thetable, all substantially as and for the purpose described.

12. In a roll-grooving-machine, the combination with the table slidingupon the frame- IOO Work, and with the mechanism for impartinglongitudinalmovement to said table, of a longitudinally movable Work-actuating shaft having a driving-Wheel thereon and supported insuitable bearings; an adjustable traversing-bar pivoted above said shaftwith its pivotal point in alignment therewith, a worm intermediate toand movably connected with said wheel and traversing bar, and supportedin bearings so as to have longitudinal movement transverse to the axisof the shaft, suhslantially as and for the purpose described.

13. In a rol1-groovngmachine, the combi nation With tho main framework,and thetable sliding thereon, of a work-actuating-shaft journaled inbearings so as to permit of lon gitudiual adjustment, and having adriving- Wheel thereon, a traversing-bar adjustably rotating saidworm-rack, substantially as and 3o for the purpose described.

FRANCIS A. PRATT. JOHN JOHNSTON. Witnesses:

FRANCIS I-I. RICHARDS, J. E. SPALDING.

